The present invention relates to packs for smoking articles, and in particular to packs for smoking articles having an inner slide and an outer shell (hereinafter referred to as slide-shell packs).
Slide-shell packs for smoking articles, such as cigarettes, differ from conventional hinged lid packs in that the smoking articles are provided in an inner shell which the user slidably moves relative to an outer shell to access the smoking articles. Some slide-shell packs have had a lid-opening mechanism that is activated by the movement of the slide within the shell.
Lid-opening mechanisms for slide-shell packs described in the prior art are mostly of the type having a connection between the outer shell and the lid of inner slide such that the lid is hinged open as the inner slide moves relative to the shell. The connection may be permanent (in which case it typically comprises an adhesive) or may rely on mechanical engagement between respective parts on the outer shell and inner slide. We are here concerned with lid-opening mechanisms which rely on mechanical engagement.
CH-A-598061 describes a cuboid slide-shell pack of conventional rectangular cross-section. The slide has a lid which includes a top wall and an upper portion of a rear side wall of the slide. The lid is hinged to the rest of the slide along a fold line at the lower edge of the upper portion of the rear side wall, and a tongue hangs from the top edge of the lid where the top wall meets the rear side wall. The tongue is folded upwardly and outwardly at a lower portion to form a hook. The outer shell carries an inwardly folded flap at an upper edge which engages with the hook when the inner slide is moved a given amount upwardly in the outer shell. This causes the tongue to exert a leverage on the top edge of the lid, and thereby hinge it open as the slide continues to move upwardly.
The construction of this lid-opening mechanism is relatively simple, but suffers a disadvantage in that an unattractive and weakening aperture is formed in the rear side wall as the lid hinges open and the tongue pivots about the top edge of the lid.
U.S. Pat. No. 4,646,960 teaches another version of a slide-shell pack having a hook and flap lid-opening mechanism, differentiated from CH-A-598061 only in that the tongue is cantilevered out from the rear edge of the lid. Again an aperture is left where the tongue material is cut from the rear wall.
U.S. Pat. No. 3,933,299 describes another cuboid slide-shell pack also having a hook and flap lid-opening mechanism at the rear of the pack. The disadvantage mentioned above is avoided by providing the hook on an extension to the lid. This extension double-backs from the front lip of the lid to the rear side wall of the inner slide. The extension provides at the rear side wall a second outer layer of material. The hook, being formed only from this outer thickness, is located adjacent an unapertured wall (i.e. the inner layer).
Although U.S. Pat. No. 3,933,299 shows how to avoid forming an aperture in the inner slide, it has the serious disadvantage of the consumption of additional pack material for manufacture of the extension.
The present invention overcomes the above disadvantages, and provides in a first aspect a cuboid pack for smoking articles, the pack having an outer shell and an inner slide;
the inner slide including a top wall and a minor side wall joined to the top wall at a top edge, the minor side wall having upper and lower wall portions and a fold line between the upper and lower wall portions, a lap seam of at least double layer thickness forming at least part of the minor side wall, the upper wall portion and at least part of the top wall forming a lid which is hingeable along the fold line;
the inner slide further including a tongue in the minor dimension of the pack and formed from the outer layer of the seam, an upper end of the tongue being attached to the upper wall portion at an attachment position above the fold line, and a hook at the lower end of the tongue;
the outer shell including a minor shell wall adjacent the said minor side wall of the slide, and having an engagement portion which is releasably engageable with the hook;
the inner slide being moveable relative to the outer shell, whereby upward movement causes the hook to engage with the engagement portion thereby hinging open the lid along the fold line.
The tongue will normally be formed integrally of the material of the outer layer of the seam of the side wall. It preferably occupies only a portion, such as for example a half or a third, of the minor dimension.
Unlike the packs described in U.S. Pat. No. 464,960 and CH-598061, in the pack of the present invention the inner layer of the lap seam can prevent an aperture being formed in the wall of the slide beneath the tongue as the lid is hinged open. However, usually a double layer seam, such as that from which the tongue is formed, is a necessary element in the construction of a slide from a folded blank. Therefore, in contrast to U.S. Pat. Nos. 3,933,299 and 4,646,960, no additional pack material need be consumed in the manufacture of the slide.
The engagement portion of the shell may conveniently be formed as an inner, downwardly-extending flap joined to the top edge of the minor shell wall, although other forms of engagement portion are not excluded. In a shell having a second minor shell wall opposing the first minor shell wall, a second engagement portion is preferably formed at the second minor shell wall such that the slide can be inserted into the shell in either of two orientations.
Preferably it is arranged that the tongue is formed from a portion of the outer layer of the lap seam which portion is spaced from the edge of the seam bounded by the free edge of the inner layer of the seam, so that the tongue is underlain by a completely continuous portion of the inner layer. Preferably also one edge of the tongue coincides with one edge of the outer wall. The pack is therefore stronger and more attractive.
Typically the lid includes a part of the top wall, the upper wall portion of the minor side wall, and opposing portions of the opposing major side walls of the slide. However, other lid configurations are not excluded.
An advantage of a lid hinged at a minor side wall and including only part of the top wall, compared with e.g. CH-A-598061, U.S Pat. Nos. 3,933,299 and 4,646,960 which show conventional hinged lids including all of a top wall and four major and minor side walls, is that a much lighter lid construction becomes possible. The hook and engagement portion mechanism therefore may be less robust. Also a lip may be provided to the lid simply by providing an extension portion to the part of the top wall included in the lid. The extension portion overlaps on that adjacent part of the top wall not included in the lid. Again, because the top wall is normally made of two layers of material, this does not involve wastage.
In a second aspect the invention provides a pack for smoking articles having an outer shell and an inner slide, the outer shell having a partial bottom wall allowing access to the base of the slide, and a plurality of substantially parallel side walls which form a guide tube for the inner slide;
the bottom wall being formed by gussets joining at least two pairs of neighbouring side walls along respective bottom edges, the planes which contain the neighbouring side walls forming an angle, and the gussets having a hinge line directed towards the apex of the angle,
whereby folding the gussets about the hinge line enables the outer shell, absent the inner slide, to be flatly foldable, and unfolding the gussets enables the outer shell to be reerectable.
Preferably the gussets are triangular, and the shell is cuboid.
Of course, the shell of this aspect of the invention may be the shell of the slide-shell pack of the invention.
The outer shell of either aspect may have a plurality of through-holes, and the inner slide bear indicia on surfaces slidable adjacent the through-holes of the shell, at least one position of the slide relative to the shell providing an alignment of the indicia with the through-holes, at which position the indicia provide a recognisable representation viewable through the through-holes.